Straight just used to be a synonym for heterosexual, as opposed to gay and homosexual. But I do think it kind of has broadened to be the opposite of queer, or a synonym for cis het.
So yes in the old sense, perhaps no in the changing sense. A heterosexual t4t couple still challenges cishet gender norms etc
Lysenko might have been wrong about a lot, but most people forget biology was basically a racist pseudoscience even into the early 20th century. Like getting a biologist who was a communist and not obsessed with phrenology or anything extra was pretty exceptional. Though you know it would have helped if he had been more correct on the science part.